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Plasmon-Enhanced Fluorescence in Gold Nanorod-Quantum Dot Coupled Systems
摘要： Plasmon-exciton coupling is of great importance to many optical devices and applications. One of the coupling manifestations is plasmon-enhanced fluorescence. Although this effect is demonstrated in numerous experimental and theoretical works, there are different particle shapes for which this effect is not fully investigated. In this work electrostatic complexes of gold nanorods and CdSe/CdZnS quantum dots were studied. Double-resonant gold nanorods have an advantage of the simultaneous enhancement of the absorption and emission when the plasmon bands match the excitation and fluorescence wavelengths of an emitter. A relationship between the concentration of quantum dots in the complexes and the enhancement factor was established. It was demonstrated that the enhancement factor is inversely proportional to the concentration of quantum dots. The maximal fluorescence enhancement by 10.8 times was observed in the complex with the smallest relative concentration of 2.5 quantum dots per rod and approximately 5 nm distance between them. Moreover, the influence of quantum dot location on the gold nanorod surface plays an important role. Theoretical study and experimental data indicate that only the position near the nanorod ends provides the enhancement. At the same time, the localization of quantum dots on the sides of the nanorods leads to the fluorescence quenching.
关键词： quantum dot fluorescence,gold nanorod-quantum dot complexes,plasmon-enhanced fluorescence,plasmon-exciton coupling,gold nanorods
更新于2025-09-11 14:15:04
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Metal-Enhanced Fluorescence of Gold Nanoclusters as a Sensing Platform for Multi-component Detection
摘要： Metal-enhanced fluorescence (MEF) has been applied to construct biosensing systems in the recent decades owing to its favorable optical properties. Herein, silver nanoparticles (AgNPs) are used to enhance fluorescence of gold nanoclusters (AuNCs), by fabricating a core-shell composite nanostructure Ag@SiO2-AuNCs consisting of a silver core, a silica shell and an outer conjugated layer of AuNCs. The core-shell MEF-capable nanoparticles possess water dispersibility, high stability and good biocompatibility. The interaction between AuNCs on the surface of the outer silica shell and the silver core, significantly improves the excitation efficiency, and thus enhances the fluorescence emission, photostability and quantum yield of the AuNCs. The composite nanoparticle Ag@SiO2-AuNCs provides a fluorescence enhancement of up to 3.21-fold when the separation distance (the thickness of the silica shell) is about 10 nm. Finally, the composite nanostructures have further been applied to develop a sensing platform for multi-component detection based on the MEF capability and the OFF-ON-OFF switching nature of the fluorescence signal, and the detection limits for Cu2+, inorganic pyrophosphate (PPi) and pyrophosphatase (PPase) are 39 nM, 78.7 nM and 0.976 mU, respectively. This platform has been applied to detect Cu2+, PPi and PPase with satisfactory results in living cells.
关键词： Metal-enhanced fluorescence (MEF),Fluorescence sensor,Core-shell composite nanostructure,Gold nanoclusters (AuNCs)
更新于2025-09-10 09:29:36
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Facile Synthesis of Resveratrol Nanogels with Enhanced Fluorescent Emission
摘要： Herein, a kind of fluorescent resveratrol nanogels via one-pot thiol-ene Michael addition polymerization of resveratrol triacrylate, 1,6-hexanedithiol, and methoxyl poly(ethylene glycol) acrylate is prepared. The resultant nanogels can be well-dispersed in water with a hydrodynamic radius of around 68 nm, and the nanogels are stable in both water and organic solvents. Moreover, the resveratrol nanogels exhibit elevated fluorescence intensity compared to free resveratrol, and the quantum yield of resveratrol nanogels is estimated to be 5.8 times as that of free resveratrol dispersed in water. Fluorescence image results also demonstrate that the resveratrol nanogels can be used for cell imaging in MCF-7 human breast cancer cells. Therefore, the resveratrol nanogels are expected to be used as a trackable drug delivery system.
关键词： resveratrol,cell imaging,thiol-ene,nanogel,enhanced fluorescence
更新于2025-09-09 09:28:46
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Visualization of Endogenous Hydrogen Sulfide in Living Cells based on Au Nanorods@Silica Enhanced Fluorescence
摘要： Hydrogen sulfide as a gas indicator molecule plays an important role in various human physiological processes. However, due to the high volatility and diffusivity of H2S in biological systems, it is very difficult to implement a precise assay for H2S detection. Compared with the destructive instrumental methods, assays based on fluorescence probes provide noninvasive and real-time detections of H2S in living cells. In this work, we presented a fluorescent nanoprobe based on dye-functionalized Au nanorods (NRs)@silica for sensitive and selective detection of H2S in vitro and living cells. With the metal enhanced fluorescence effect, the fluorescence turn-on and turn-off were controlled by the formation and disassembly of coordination compound between dyes and copper ions. Silica matrix was used to coat the Au NRs to prevent them from the biological cytotoxicity. The effects of the different distances between Au NRs and fluorophores on fluorescent enhancement were explored and approximately 5-fold fluorescence enhancement was obtained with a distance of 22 nm. A detection of limit of 17 nM was achieved. In addition, visualization of exogenous and endogenous H2S in living cells was validated.
关键词： nanoprobes,Au nanorods@silica,metal enhanced fluorescence,living cells,endogenous H2S
更新于2025-09-04 15:30:14
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[IEEE 2018 Photonics North (PN) - Montreal, QC, Canada (2018.6.5-2018.6.7)] 2018 Photonics North (PN) - Bloch Surface Wave Based Biosensing
摘要： An integrated biosensing platform exploiting the properties of Bloch surface waves on all-dielectric thin film stacks is described. It combines label-free sensing based on tracking with surface wave enhanced angular resonance fluorescence and detection. Detailed design considerations reveal a system with defined attenuation to improve resolution limits in both modes.
关键词： label-free detection,biosensor,Bloch surface wave,1D photonic crystal,surface wave enhanced fluorescence
更新于2025-09-04 15:30:14